Bioaccumulation Of Nanoparticles Research Articles

Entering a New Agricultural Era through the Impact of Nano-Fertilizers on Crop Development: A Review

The dynamic interface between nanotechnology and agriculture heralds a new era in food production, with nano-fertilizers standing at the forefront of this revolution. These fertilizers, leveraging the unique properties of nanoparticles, promise to address several challenges posed by traditional fertilization methods, including nutrient wastage, environmental pollution, and inconsistent yields. Preliminary studies indicate that nano-fertilizers can enhance nutrient uptake, allowing for direct and efficient nutrient transfer to plant cells, leading to improved crop yields. Their targeted delivery mechanisms mitigate nutrient loss through leaching, presenting a more environmentally friendly alternative. Yet, alongside these potential benefits, the introduction of nanoparticles into agriculture poses significant challenges. There are growing concerns regarding their long-term environmental impact, specifically the accumulation of nanoparticles in various ecosystems and the subsequent implications for flora and fauna. Potential health risks for both consumers and farm workers also warrant in-depth research, with questions arising about the bioaccumulation of nanoparticles in plants and their subsequent effects when consumed. The possibility of the emergence of nanoparticle-resistant pests, mirroring the historical challenges with pesticide-resistant strains, adds another layer of complexity to the narrative. Policymakers face the intricate task of creating dynamic regulatory frameworks. These need to facilitate the advancement and adoption of nano-fertilizers while ensuring the safety of both the environment and consumers. Such frameworks should be predicated on robust scientific research, encompassing not just immediate crop yield outcomes but broader ecological, health, and socio-economic impacts. Looking ahead, as the field of nanotechnology continues to evolve rapidly, the agricultural sector stands at a pivotal juncture. Embracing the advantages of nano-fertilizers could fundamentally reshape farming practices, driving them towards greater sustainability and efficiency. This transition needs to be navigated with a clear vision, grounded in rigorous scientific inquiry and underpinned by comprehensive policies, to ensure that the agriculture of tomorrow is both bountiful and sustainable.

Pre-exposure to Fe2O3 or TiO2 Nanoparticles Inhibits Subsequent Biological Uptake of 55Fe-Labeled Fe2O3 Nanoparticles

Aquatic organisms are frequently exposed to various nanoparticles (NPs) in the natural environment. Thus, studies of NP bioaccumulation should include organisms that have been previously exposed to NPs. Our study investigated the effects of pre-exposure of Tetrahymena thermophila (T. thermophila) to Fe2O3 or TiO2 NPs on the protozoan's subsequent uptake of 55Fe-labeled Fe2O3 (55Fe2O3) NPs. Molecular mechanisms underlying the pre-exposure effects were explored in transcriptomic and metabolomic experiments. Pre-exposure to either NPs inhibited the subsequent uptake of 55Fe2O3 NPs. The results of the transcriptomic experiment indicated that NP pre-exposure influenced the expression of genes related to phagosomes and lysosomes and physiological processes such as glutathione and lipid metabolism, which are closely associated with the endocytosis of 55Fe2O3 NPs. The differentially expressed metabolites obtained from the metabolomic experiments showed an enrichment of energy metabolism and antioxidation pathways in T. thermophila pre-exposed to NPs. Together, these results demonstrate that the pre-exposure of T. thermophila to Fe2O3 or TiO2 NPs inhibited the protozoan's subsequent uptake of 55Fe2O3 NPs, possibly by mechanisms involving the alteration of endocytosis-related organelles, the induction of oxidative stress, and a lowering of the intracellular energy supply. Thus, NP pre-exposure represents a scenario which can inform increasingly realistic estimates of NP bioaccumulation.

Determining the common patterns of the action of nanoparticles of various compositions and structures on physiological and biochemical processes in plants

Technogenic and natural nanomaterials are alien to living systems. The negative effect of nanomaterials may be due to their accumulation in intracellular organelles. The properties of nanoparticles are determined not only by their size, which manifests itself in the activation of a thermodynamic variable, but also by their chemical structure and shape, their ability to aggregate. The effect of metal nanoparticles and oxides of cobalt and titanium on the development and growth of plants has been studied. An important established fact is the ability of oxide nanoparticles, unlike metals themselves, to accumulate in living systems. Transmission electron microscopy, carried out by means of electron microscopic analysis, has revealed interstitial bioaccumulation of nanoparticles of cobalt oxide and titanium oxide in the form of aggregates 80-300 nm in size. If nanoparticles quickly aggregate, they are less dangerous for organisms than single nanoparticles, since a large aggregate of nanoparticles cannot get inside the cell. The rate and dynamics of deposition of nanoparticles of metals and their oxides in water are different. Metal NPs are deposited much more slowly than titanium dioxide. Moreover, the safety of NPs depends on their size and concentration. Biogenic nanoparticles with a size of 35-75 nm have high biological activity, biocompatibility and environmental safety. There is a direct correlation between the energy produced in cells, which is necessary for seed viability, and an increase in the number of protons under the action of metal nanoparticles, which leads to an increase in the permeability of cell membranes and the activity of enzymes and phytohormones.

Nanoparticles and Nanomaterials-Based Recent Approaches in Upgraded Targeting and Management of Cancer: A Review.

Along with the extensive improvement in tumor biology research and different therapeutic developments, cancer remains a dominant and deadly disease. Tumor heterogeneity, systemic toxicities, and drug resistance are major hurdles in cancer therapy. Chemotherapy, radiotherapy, phototherapy, and surgical therapy are some prominent areas of cancer treatment. During chemotherapy for cancer, chemotherapeutic agents are distributed all over the body and also damage normal cells. With advancements in nanotechnology, nanoparticles utilized in all major areas of cancer therapy offer the probability to advance drug solubility, and stability, extend drug half-lives in plasma, reduce off-target effects, and quintessence drugs at a target site. The present review compiles the use of different types of nanoparticles in frequently and recently applied therapeutics of cancer therapy. A recent area of cancer treatment includes cancer stem cell therapy, DNA/RNA-based immunomodulation therapy, alteration of the microenvironment, and cell membrane-mediated biomimetic approach. Biocompatibility and bioaccumulation of nanoparticles is the major impediment in nano-based therapy. More research is required to develop the next generation of nanotherapeutics with the incorporation of new molecular entities, such as kinase inhibitors, siRNA, mRNA, and gene editing. We assume that nanotherapeutics will dramatically improve patient survival, move the model of cancer treatment, and develop certainty in the foreseeable future.

The Effects of Combined toxicity of Silver and Silicon Nanoparticles on Hematological and Biochemical Parameters in Male Albino Mice

In this study, the potential combined effects of silver (AgNPs) and silicon dioxide nanoparticles (SiO2NPs) on male albino mice which were exposed intraperitoneally to the 50 mg/kg and 100 mg/kg and mixed concentrations of nanoparticles (NPs) for periods of 2 and 4 weeks, were evaluated. The evaluation was performed by examining the haematological and biochemical parameters, in addition to the bioaccumulation of NPs in the liver and kidney. The results showed that the platelets count significantly increased in all exposed groups, while red blood cell count (RBCs) decreased in most exposed groups. White blood cells (WBCs) and haemoglobin (Hb) showed different levels in the exposed groups. Serum aspartate aminotransferase (AST) and serum alanine aminotransferase (ALT) levels also showed a significant increase in the exposed groups, except in the groups exposed to 100 mg/kg of NPs for 2 weeks. Whereas blood urea nitrogen) BUN) serum level showed a significant decrease in all exposed groups. However, the alkaline phosphatase (ALP), uric acid (UA) and creatinine (CR) levels did not show any significant alternations in the exposed groups. Significant increase was also noted in thyroid-stimulating hormone (TSH) levels among the exposed groups. An accumulation of AgNPs and SiO2NPs was observed both in livers and kidneys in the exposed groups. The results showed that SiO2NPs have a synergistic effect on AgNPs accumulation in the groups exposed to mixed nanoparticles.

Zinc oxide, titanium dioxide and C60 fullerene nanoparticles, alone and in mixture, differently affect biomarker responses and proteome in the clam Ruditapes philippinarum

Continuous release of nanoparticles (NPs) into marine coastal environments results in an increased risk of exposure to complex NP mixtures for marine organisms. However, to date, the information on the effects at molecular and biochemical levels induced by the exposure to NPs, singly and as a mixture, is still scant. The present work aimed at exploring the independent and combined effects and the mechanism(s) of action induced by 7-days exposure to 1 μg/L nZnO, 1 μg/L nTiO2 and 1 μg/L FC60 fullerene in the Manila clam Ruditapes philippinarum, using a battery of immunological and oxidative stress biomarkers in haemolymph, gills and digestive gland. In addition, proteomics analyses were performed in gills and the digestive gland, where NP bioaccumulation was also assessed. Increased bioaccumulation of single NPs and the mixture was linked with increased oxidative stress and higher damage to proteins, lipids and DNA in all tissues analysed. The proteomics approach highlighted protein modulation in terms of abundance and damage (higher redox-thiol and carbonylated groups content). In particular, the modulated proteins (16 in gills and 18 in digestive gland) were mostly related to cytoskeleton and energetic metabolism. The digestive gland was the tissue more affected. For all biomarkers measured, increased detrimental effects were observed in the mixture compared to single NP exposures.

Uptake and bioaccumulation of nanoparticles by five higher plants using single-particle-inductively coupled plasma-mass spectrometry

The exposure risk of nano-enabled products towards plants and related food safety.

Bioaccumulation but no biomagnification of silver sulfide nanoparticles in freshwater snails and planarians

Bioaccumulation studies are critical in regulatory decision making on the potential environmental risks of engineered nanoparticles (NPs). The present study evaluated the toxicokinetics of silver, taken up from sulfide nanoparticles (Ag2S NPs; simulating an aged Ag NP form) and AgNO3 (ionic counterpart), in the pulmonate snail Physa acuta and the planarian Girardia tigrina. The snails were first exposed for 7 days to Ag-spiked water, along with the microalgae Raphidocelis subcapitata upon which they fed setting up a double route exposure, and subsequently provided as pre-exposed food to the planarians. Ag toxicokinetics and bioaccumulation were assessed in planarians and snails, and potential biomagnification from snail to planarian was evaluated. Gut depuration was also explored to understand whether it constitutes a factor likely to influence Ag toxicokinetics and internal concentrations in the test species. Both species revealed Ag uptake in Ag2S NP and AgNO3 treatments, with higher uptake from the latter. Uptake by the snails was probably via a combination of water exposure and ingested algae provided as food, but ingestion of algae possibly had higher relevance for Ag uptake from the Ag2S NPs compared to AgNO3. For planarians, diet probably was the most important exposure route since no Ag uptake was observed in previous waterborne exposures to Ag2S NPs. Kinetics and internal Ag concentrations did not significantly differ between depurated and non-depurated snails or planarians. The planarians fed on snails revealed no biomagnification. To the best of our knowledge this is the first study investigating the toxicokinetics and biomagnification of NPs in planarians, and with that providing important data on the kinetics and bioaccumulation of NPs in a relevant benthic species.

Features of bioaccumulation and toxic effects of copper (II) oxide nanoparticles under repeated inhalation exposure in rats

Introduction. Active use in various spheres of economic activity, large-scale production and the availability of data on toxicity determine the relevance of studying the effects of copper (II) oxide nanoparticles (CuO NPs) on the body during inhalation exposure. Material and Methods. The size, surface area, and pore volume of CuO NPs were determined. The study and assessment of biochemical and hematological parameters of blood, the degree of bioaccumulation of nanomaterial, pathomorphological changes in organs of rats exposed to CuO NPs were carried out. The studies were carried out in comparison with a microsized analogue (CuO MPs). Results. The size of CuO NPs in the composition of the native powder is 305.00 times less than that of CuO MPs. The surface area and pore volume are 9.61 and 9.33 times larger, respectively. After exposure to CuO NPs in the blood of rats relative to the control, the levels of activity of ALT, AST, ALP, GGT, LDH, amylase, AOA, MDA and the concentration of CRP increased by 1.49-2.23 times, the content of urea decreased by 1.41 times; relative number of eosinophils, leukocyte count, RDW by 1.31-5.39 times increased, relative number of segmented neutrophils decreased by 1.37 and monocytes by 1.42 times. The effect of NPs, in comparison with MPs, is more pronounced in increasing the activity of ALT, AST, LDH, MDA and the concentration of CRP by 1.25-1.68 times and in reducing the concentration of urea by 1.21 times; in increase the relative number of eosinophils by 2.37 and the count of leukocytes by 1.61 times. The concentration of copper under the action of NPs increases relative to the control in the lungs, liver, stomach, intestines and kidneys by 1.59-6.99 times. The degree of bioaccumulation of nanoparticles is 1.20-2.12 times higher than that of microparticles in the lungs, liver, stomach, and kidneys. Conclusion. Functional and pathomorphological changes caused by CuO NPs are more pronounced in the lungs, stomach, and small intestine in comparison with microparticles. It was confirmed that the studied CuO particles are nanomaterials. They have a more pronounced bioaccumulation and toxic effect relative to the microdispersed analogue.

Cell Cycle Control of Nanoplastics Internalization in Phytoplankton.

Nanoparticles (NPs) for delivering chemotherapeutic drugs are now in clinical trials, and cellular uptake of NPs plays an important role in determining the drug delivery efficiency. Herein, we reported that the bioaccumulation and internalization of NPs were governed by the cell cycle. Specifically, we found that the bioaccumulation of NPs was more favored in the G2/M stages, followed by the S and G0/G1 stages. We demonstrated that three key parameters-clathrin-mediated endocytosis capacity, algal cell membrane permeability, and exopolymer substance (EPS) thickness-were critical in the bioaccumulation of NPs during the cell cycling process. Over the 24-h average duration of cell cycle, clathrin-mediated endocytosis capacity was much higher at the S stage than that at the G0/G1 and G2/M stages. Besides, cell membrane permeability was measured to be higher in S and G2/M stages while the lowest in G0/G1 stage. We have also identified the change of EPS thickness during the 24-h cell cycle. Transition from G0/G1 to S and G2/M induced the attenuation in EPS thickness, and the thinnest EPS was found at the end of mitosis. The cell cycle control NPs internalization were further verified by exposing Ag nanoparticles to algae at different cell cycle stages, confirming the important roles of EPS thickness and cell cycle control in the dynamic internalization processes. The present study highlights the important roles of cell cycle controlling the NPs bioaccumulation and internalization, with possible implications in maximizing NPs internalization efficiency while reducing the cost.

Effects of extracellular polymeric substances on silver nanoparticle bioaccumulation and toxicity to Triticum aestivum L.

The potential effects of extracellular polymeric substances (EPS) on the behavior and toxicity of silver nanoparticle (Ag-NPs) and silver sulfide nanoparticle (Ag2S-NPs) remains ambiguous. The interaction of EPS from Bacillus subtilis with Ag2S-NPs, metallic Ag-NPs, or ionic Ag, and the associated plant safety had been examined in this study. The biological impacts of Ag-NPs and Ag2S-NPs were Ag form-dependent and highly influenced by microbial EPS. Compared with metallic Ag-NPs, Ag2S-NPs exert inert biological impacts, as revealed by 3.44 times lower Ag bioaccumulation in wheat (Triticum aestivum L.) seedlings and nearly reduce plant biomass when wheat was subjected to 1.0 mg-Ag L−1 of Ag-NPs and Ag2S-NPs with the transfer factors of 151.56–930.87 vs. 12.52–131.81, respectively. These observations were coincident with the low dissolved Ag ([Ag]diss) in the Ag2S-NPs treatment than the Ag-NPs treatment (114.0 vs. 0.0791, μg L−1). Compared with the enhanced toxicity of Ag2S-NPs to wheat, Bacillus subtilis EPS significantly alleviate the phytotoxicity of Ag-NPs, as revealed by the relative root elongation (7.15–45.40% decrease vs. 2.39–11.75% increase), and malondialdehyde (1.47–83.22% increase vs. 8.57–25.25% decrease) and H2O2 (11.27–71.78% increase vs. 5.16–36.67% decrease) contents. These constrasting plant responses of B. subtilis EPS are mainly caused by their complexation property with toxic Ag+ and nutrient elements for wheat stressed by Ag-NPs and Ag2S-NPs, respectively. Our findings highlight the importance of rhizospheric EPS in affecting the biogeochemistry and ecotoxicity of metal nanoparticles including Ag-NPs and Ag2S-NPs in agricultural systems.

Accumulation of metal-based nanoparticles in marine bivalve mollusks from offshore aquaculture as detected by single particle ICP-MS

The exposure risk of metal-based nanoparticles (NPs) to marine organisms and related food safety have attracted increasing attention, but the actual concentrations of these NPs in seawater and marine organisms are unknown. In this work, single particle inductively coupled plasma-mass spectrometry (spICP-MS) was used to quantify the concentrations and size distributions of NPs in different marine mollusks (oysters, mussels, scallops, clams, and ark shells) from an offshore aquaculture farm. Results showed that Ti, Cu, Zn, and Ag bearing NPs were detected in all the five mollusks with the mean sizes at 65.4–70.9, 72.2–89.6, 97.8–108.3, and 42.9–51.0 nm, respectively. The particle concentrations of Ti, Cu, Zn, and Ag bearing NPs in all mollusks (0.88–3.26 × 107 particles/g fresh weight) were much higher than that in the seawater (0.46–0.79 × 107 particles/mL), suggesting bio-accumulation of NPs. For all the five mollusks, Ag bearing NPs had the highest number-based bioconcentration factors (NBCFs) in all the tested NPs due to the smallest mean size of Ag bearing NPs in seawater (30.5 nm). In addition, the clams exhibited the lowest NBCFs of the four NPs than other mollusks. All four NPs were mainly accumulated in the gill and digestive gland, and could transfer to adductor muscle of all mollusks. Although all the four metals (Ti, Cu, Zn, Ag) in mollusks were safe for human consumption by the estimated daily intake (EDI) analysis, the risk of NPs remaining in the mollusks should be further considered when evaluating the toxicity of metals for human health. The findings could improve our understanding on the distribution and health risk of NPs in marine mollusks under offshore aquaculture.

Morphostructural and immunohistochemical study for evaluation of nano-TiO2 toxicity in Armadillo officinalis Duméril, 1816 (Crustacea, Isopoda, Oniscidea).

Invertebrates are precious organisms in order to study environmental pollution. In particular, they appear to be suitable as a bioindicator species for pioneer ecotoxicity studies on new xenobiotics such as nanoparticles. In fact, they are able to absorb nanomaterials scattered in the environment in different ways and it's known the compartmentalization of nano-sized contaminants in selected tissues and intracellular organelles. Titanium dioxide represents the most used nanoparticulate, destined to become probably ubiquitous in the environment. Recently, some research has been published on the toxic potential of nano-TiO2 in several animal species. Among all invertebrates, Oniscidean Isopods are the only taxon of Crustaceans that has become completely terrestrial, known as excellent bioindicators and bioaccumulators. They have a digestive gland, the hepatopancreas, which is the location of election for the accumulation of pollutants. For this reason, they are considered efficient animal models to ecological studies. For this study, we collected Armadillo officinalis from Natural Oriented Reserve of "Vendicari" (Sicily, Italy), to evaluate the toxicity of titanium dioxide (TiO2 ) on their hepatopancreas, after a short period of exposure. We conducted morphostructural and immunohistochemistry assays. The results suggested a great capacity of the species of bioaccumulation of nanoparticles in the hepatopancreas, where a strong positivity to the metallothioneins was highlighted. Our study confirms that Oniscidean Isopods, in particular Armadillo officinalis, proved to be an appropriate indicator of pollution in terrestrial ecosystems from nanoparticles.

Ocean acidification increases the accumulation of titanium dioxide nanoparticles (nTiO2) in edible bivalve mollusks and poses a potential threat to seafood safety

Large amounts of anthropogenic CO2 in the atmosphere are taken up by the ocean, which leads to ‘ocean acidification’ (OA). In addition, the increasing application of nanoparticles inevitably leads to their increased release into the aquatic environment. However, the impact of OA on the bioaccumulation of nanoparticles in marine organisms still remains unknown. This study investigated the effects of OA on the bioaccumulation of a model nanoparticle, titanium dioxide nanoparticles (nTiO2), in three edible bivalves. All species tested accumulated significantly greater amount of nTiO2 in pCO2-acidified seawater. Furthermore, the potential health threats of realistic nTiO2 quantities accumulated in bivalves under future OA scenarios were evaluated with a mouse assay, which revealed evident organ edema and alterations in hematologic indices and blood chemistry values under future OA scenario (pH at 7.4). Overall, this study suggests that OA would enhance the accumulation of nTiO2 in edible bivalves and may therefore increase the health risk for seafood consumers.

Innate Immunity Provides Biomarkers of Health for Teleosts Exposed to Nanoparticles.

In recent years, the unique properties of nanoparticles have fostered novel applications in various fields such as biology, pharmaceuticals, agriculture, and others. Unfortunately, their rapid integration into daily life has also led to environmental concerns due to uncontrolled release of nanoparticles into the aquatic environment. Despite increasing awareness of nanoparticle bioaccumulation in the aquatic environment, much remains to be learned about their impact on aquatic organisms and how to best monitor these effects. Herein, we provide the first review of innate immunity as an emerging tool to assess the health of fish following nanoparticle exposure. Fish are widely used as sentinels for aquatic ecosystem pollution and innate immune parameters offer sensitive and reliable tools that can be harnessed for evaluation of contamination events. The most frequent biomarkers highlighted in literature to date include, but are not limited to, parameters associated with leukocyte dynamics, oxidative stress, and cytokine production. Taken together, innate immunity offers finite and sensitive biomarkers for assessment of the impact of nanoparticles on fish health.

The effect of zinc oxide nanoparticles bioaccumulation in seedlings on growth and development of vetch (Vicia sativa)

This paper shows the possibility of accumulation of zinc nanoparticles in vetch seedlings (Vicia sativa) and their influence on the morpho-physiological and biochemical parameters of plant development when germinating seeds on a gel-like cultivation medium. The stability of nanoparticles in this medium is shown, which is an important parameter for the validity and reliability of the results obtained. When using various methods of electron microscopy, transmission (TEM) and scanning (SEM), the adhesion of nanoparticles on the surface of plants and their accumulation in apexes and roots of seedlings is shown. The physical-chemical characteristics of zinc oxide have been revealed: the composition and morphology of the particles. The reasons for zinc oxide accumulation are apparently the following ones: high adhesion to surfaces of living systems, negative charge, nanoparticle size, solubility and sustainable formation of agglomerates. For zinc oxide nanoparticles, changes in the activities of peroxidase and superoxide dismutase enzymes are more than 30% with a concentration of nanoparticles above 10.0 g/t, which proves slower plant growth. Consequently, a significant deviation of parameters of the biochemical status of plants from the norm can serve as a signal of a toxic effect of nanoparticles. The effect of zinc oxide nanoparticles on the activity of vetch phytohormones has been studied. In the concentration range of 0.001-1.0 g/t, the content of indole acetic acid (IAA) under the action of nanoparticles increases, and the energy efficiency of plant respiration increases, which leads to large changes in the activity of various enzymic reactions and positive dynamics of growth and development of vetch seedlings. When concentrations increase above 1.0 g/t, IAA values decrease. Biologically active nanoparticles, acting on the level of phytohormones, can influence the state of bio membranes and indirectly act as a regulator of protein synthesising cells of plants, which leads, depending on the concentration of nanoparticles, to growth or inhibition of the development of living systems. The concentration of zinc oxide nanoparticles of 10 g/t of seeds, when all morpho-physiological and biological parameters indicate some inhibition of vetch growth and development, is particularly dangerous.

Fate of the nanoparticles in environmental cycles

Nanoparticles (NPs) are ubiquitous in everyday life. Due to their physicochemical, bespoken properties, they are currently exploited in a large amount of professional, recreational and daily-care items. Textiles, building materials, sunscreens, household cleaning products, agrochemical-specific biomolecules, tattoo inks are all sources of NPs. Inevitably the extended employment of NPs has an impact on the environment, which depends not only on their properties, but also on the method used for their disposal and on the physical and biochemical characteristics of the disposal location. These parameters eventually determine both the NPs bioaccumulation and their ecotoxicity. In this review, the environmental fate of the most commonly used NPs, i.e., Ag-NPs, ZnO-NPs and TiO2-NPs, are overviewed, taking into account the most up-to-date studies. Furthermore, the issues related to the trophic transfer and to the current nanomaterial regulations are reported.

Analysis of gold and silver nanoparticles internalized by zebrafish (Danio rerio) using single particle-inductively coupled plasma-mass spectrometry

With the increase in the application of nano-consumer products containing engineered nanoparticles (NPs), the unintended environmental exposure to NPs has been inevitable. Because of the bioaccumulation of NPs, concern about their potential cytotoxicity to aquatic organisms is also growing. Although measuring tools for analyzing particle size and/or concentration of NPs in intracellular uptake of tissues have been well developed, a simultaneous analysis of the two characteristics is difficult. The objective of this study was to use single particle-inductively coupled plasma-mass spectrometry (sp-ICP-MS) to measure the bioaccumulation and particle size changes of NPs exposed to zebrafish (Danio rerio) for 7 days. The uptake of NPs in the liver, intestine, and gill tissues was confirmed by electron microscopic (EM) analysis. However, the primary particle size of NPs in tissues could not be determined by the EM analysis. Therefore, sp-ICP-MS coupled with alkaline digestion was used for the easy extraction and immediate analysis of NPs from tissues. Zebrafish were exposed to four NPs (30 and 80 nm gold/silver NPs; AuNPs/AgNPs). Uptake amounts of AgNPs in the liver and intestine were significantly higher than those of AuNPs. Although larger NPs were finally accumulated in the liver and intestine tissues, most of the smaller NPs were filtered in the gills. The sp-ICP-MS method coupled with alkaline digestion enabled the accurate analysis of size, size distribution, and mass concentration of NPs in an aquatic organism.

Titanium Dioxide Nanoparticle Circulation in an Aquatic Ecosystem

Nanotechnology is a dynamically developing field of scientific and industrial interest across the entire world, and the commercialization of nanoparticles (NPs) is rapidly expanding. Incorporation of nanotechnologies into a range of manufactured goods results in increasing concern regarding the subsequent release of engineered NPs into the environment. One of the biggest threats of using NPs is the transfer and magnification of these particles in the trophic chain. The aim of the studies was the evaluation of the distribution of TiO2 NP contamination in the aquatic ecosystem under laboratory conditions. Bioaccumulation of TiO2 NPs by plants (Elodea canadensis) and fish (Danio rerio) in the source of contamination was investigated. The studies were focused on the consequences of short-term water contamination with TiO2 NPs and the secondary contamination of the components of the investigated model ecosystem (plants, sediments). It was found that in the fish and the plants exposed to NP contamination, the amount of Ti was higher than in the control, indicating an effective bioaccumulation of NPs or ions originating from NPs. It was clearly shown that the NPs present in the sediments are available to plants and fish. Additionally, the aquatic plants, an important trophic level in the food chain, can accumulate NPs and be a source of NPs for higher organisms. It was concluded that even an incidental contamination of water by NPs may result in long-term consequences induced by the release of NPs.

The Toxicity of Nanoparticles to Organisms in Freshwater.

Nanotechnology is a rapidly growing industry yielding many benefits to society. However, aquatic environments are at risk as increasing amounts of nanoparticles (NPs) are contaminating waterbodies causing adverse effects on aquatic organisms. In this review, the impacts of environmental exposure to NPs, the influence of the physicochemical characteristics of NPs and the surrounding environment on toxicity and mechanisms of toxicity together with NP bioaccumulation and trophic transfer are assessed with a focus on their impacts on bacteria, algae and daphnids. We identify several gaps which need urgent attention in order to make sound decisions to protect the environment. These include uncertainty in both estimated and measured environmental concentrations of NPs for reliable risk assessment and for regulating the NP industry. In addition toxicity tests and risk assessment methodologies specific to NPs are still at the research and development stage. Also conflicting and inconsistent results on physicochemical characteristics and the fate and transport of NPs in the environment suggest the need for further research. Finally, improved understanding of the mechanisms of NP toxicity is crucial in risk assessment of NPs, since conventional toxicity tests may not reflect the risks associated with NPs. Behavioural effects may be more sensitive and would be efficient in certain situations compared with conventional toxicity tests due to low NP concentrations in field conditions. However, the development of such tests is still lacking, and further research is recommended.